Combination lock



April 14, 1970 F. G. SlNCLAlR COMBINATION LOCK Filed Aug. 12. 1968 INVENTOR FRED G. SINCLAIR United States Patent US. Cl. 70350 4 Claims ABSTRACT OF THE DISCLOSURE A combination lock having a housing in which a pin plate support is slidably mounted and actuated by a lock bolt support with a back plate having openings removably mounted on the housing and in carrying plate removably mounted on the pin plate support, the pins being in alignment with the openings in the back plate when the lock is in its locked position. Upon sliding movement of the pin plate support a certain distance, the pins are brought out of the alignment with the openings in the back plate when the lock is in its locked position. Upon sliding movement of the pin plate support a certain distance, the pins are brought out of alignment with the openings in the back plate, but upon inserting a key having identical openings as said back plate in the path of movement of the pins,

the pins are received by the openings in the key and main-- This invention relates to locks and is more particularly directed to combination locks having a pin carrying plate member wherein a key and a back plate having matching openings in arrangement and in shape are utilized to release a bolt of a lock.

At the present time, it requires a skilled person such as a locksmith to change a lock or its combination so as to require a different key to open same. In the case of hotels, motels and other accommodations for hire, locks should be changed with each turnover of occupants, since a former occupant can have a duplicate key made for the purpose of breaking into the room when others later occupy the room.

Because of the high cost and time consuming efforts as well as special skill required to change conventional locks or their combinations, burglaries, and unlawful breakins are prevalent and considered as unavoidable by operators of hotels, motels, etc.

The present invention contemplates avoiding such a situation so that with each different occupant a different key is required to enter the premises.

Therefore a principal object of the present invention is to provide a lock whose key can be changed by merely removing a pin plate and back plate and replacing them with different pin and back plates that require a new key to operate the lock.

Another object of the present invention is to provide a combination lock having a back plate and a pin plate carrying a plurality of pins that engage the back plate to prevent the opening of a locked door until a key having a plurality of openings matching the openings in the back plate is first inserted in the lock. A still another object of the present invention is to provide a combination lock which can be changed to require a different key to open the lock by readily removing the back and pin plates and inserting a new back and pin plate therein.

A still further object of the present invention is to provide a combination lock capable of millions of combinations requiring a key for each combination in opening the lock and With the usual master keys all of which are simple in construction, inexpensive in cost and in changing the locks to require a different key and most effective ice in its operation to open easily and yet frustrate one not having the proper key.

With these and other objects in view, the invention will be best understood from a consideration of the following detailed description taken in connection with the accom panying drawings forming a part of this specification, with the understanding, however, that the invention is not confined to any strict conformity with the showing of the drawings but may be changed or modified so long as such changes or modifications mark no material departure from the salient features of the invention.

In the drawings:

FIGURE 1 is a fragmentary perspective view of a wall and door on which a lock embodying my invention is mounted.

FIGURE 2 is a sectional perspective view of my lock with the housing removed and parts broken away.

FIGURE 3 is a fragmentary end view of the door at the position of my lock.

FIGURE 4 is a rear side or inside view of my lock.

FIGURES 5 and 6 are progressive diagrammatic views of my lock showing the attempt to operate the lock without a key.

FIGURE 7 is a similar view when the proper key has been inserted in the lock.

Referring to the drawings wherein like numerals are used to designate similar parts throughout the several views, the numeral 10' refers to a lock constructed in accordance with my invention shown in position on a conventional door 11 hinged in an opening 12 in a wall 13.

Mounted on the door 11 on its outside and inside surfaces are plates 14 and 15 respectively fastened together by bolts 16 extending through the inside plate 15 and threaded into threaded tubular members 16 secured to the outside plates 14. The outside plate 14 is provided with a slot 18 for receiving a key 20 that operates the lock 10 as is disclosed in detail hereinafter while the inside plate 15 is provided with an opening 21 which a hinged cover 22 encloses. The opening 21 permits the insertion of a back plate 25 in the lock 10 and the easy replacing of the back plate 25 by another back plate when changing the lock as is explained hereinafter.

Mounted on the door plates 14 and 15 for rotational movement is a knob shaft 26 on the ends of which are door knobs 27. The mechanism of my lock 10 is contained in a housing H that consists of a front wall 28, a

top wall 29, a bottom wall 30 and an end wall 37. The bottom wall 30 is slotted as at with a bevelled surface 36 forming a juncture between the upper surfaces of the bottom wall 30 and the slot 35. The end wall 37 which is provided with an opening 23 is joined to the bottom wall 30 and top wall 29 by stepped portions formed by vertical flanges 31 and 32 mounted at the edges of horizontal flanges 34 and 39 respectively. The latter flanges are each provided with a pair of aligned slotted portions 40 and 41 to slidably receive the back plate 25 and key 20 respectively.

The front wall 28 is provided with an opening 43 through which a slide bolt 44 extends and becomes locked when received by an opening 24 in the striker plate 45 mounted on'the jamb of the wall 13. The inner end of the lock bolt 44 is secured to the front wall 46 of a lock bolt support frame L which is provided with a cam plate or rear wall 47 joining'the front wall 46 of the lock bolt support frame L by means of the top and bottom walls 48 and 49. The door knob shaft 26 e'iitends through the mid-portion of the lock bolt support frame L and has a triangular shaped cam 50 secured thereon. The cam 50 bears against the cam plate or rear wall 47 when the knobs 27 and the shafts 26 are rotated to slide the lock bolt support L rearwardly.

The lock bolt support frame L is slidably mounted within a pin plate support frame P consisting of a front wall 51, top wall 52, bottom Wall 53 and rear wall 54. The rear wall 54 which extends the full width of the housing bottom wall 30 is provided with a slotted portion 57 formed by horizontal flanges 55 joining the rear wall 54 and vertical flanges 56 mounted on the free edge of the horizontal flanges 55. The outer surfaces of the flanges 55 are provided with a raised surface 19 which normally engages the inner surfaces of the housing Walls 29 and 30 when the lock is in its locked position shown by FIGURE 5. The lower raised surface or ridge portion 19 engages the surface of the slotted portion 35 when the knob 27 has to be rotated with no key or a wrong key inserted in the slot 57. When the proper key 20 has been inserted in the slot 57, upon rotating the knob 27, the lower raised surface 19 will not engage the slotted portion but will find itself in spaced relation above the surface of the slotted portion 35 as shown by FIGURE 7.

A pin plate 58 which is slidably positioned in the slotted portion 57 consists of a plate member 59 on which is a plurality of pins 60 mounted thereon.

There may be any desired number in any desired arrangement of pins 60 mounted on the plate member 59 and these pins 60 may have any desired cross sectional configuration or shape, provided however that the key 20 and the punched back plate 25 each have openings 61 and 62 are matched with each other and with the pins 60 as is explained in detail hereinafter.

Coil springs 63 secured to the front wall 46 of the lock bolt support L extend through openings in the front wall 51 of the pin plate support member P and are fastened to the front wall 28 of the housing H. The coil springs 63 yieldingly maintain the lock bolt support L and pin plate support member P in their forward position and when the front walls 28, 51 and 46 are in contact relation, the lock bolt 44 is in its extended or locked position as shown by FIGURE 5.

In the normal use of my combination lock 10, a pin plate 58, a punched back plate 25 and a key 20 forming a set for the lock 10 are selected and the punched back plate 25 inserted through the opening 21 into the slots 41 adjacent the rear wall 37 of the housing H while the pin plate 58 is inserted into the slots 57. It is to be noted that the openings 62 in the punched plate 25 must conform with the configuration, arrangement, shape and size of the pins 60 so that when the pins 60 are aligned with the openings 62, the openings 62 will receive the pins 60. The pins 60 can be brought into alignment with the openings 62 only when the proper key 20 has been inserted into the slot 18 and received by the slots 40 to be positioned adjacent to the punched back plate 25.

As shown by FIGURE 5, the lock 10 is in its locked position with the slide bolt 44 received by the opening 24 in the striker plate 45 and held therein by the coil springs 63. When the knob 27 is rotated without the proper key inserted in place through the slot 18, the lock bolt support L will slide to the right as seen in FIG- URES 5 and 6 against the spring forces 63 by virtue of the rotating cam engaging the cam plate wall 47. When the rear wall 47 of lock bolt support L engages the rear wall 54 of the pin plate support P the latter begins to slide to the right within the housing H. The raised surfaces 19 will slide along the walls 29 and 30 of the housing. When there is no key 20 or a wrong key positioned in the slots 57, then when the lower raised surface 19 slides along the bevelled surface 36, and drops down into the slotted portion 35, the entire pin plate support P will become tilted and the pins 60 will find themselves out of alignment with the openings 62 in the punched back plate 25 as shown by FIGURE 6. The knob 27 is unable to turn any further and with the slide bolt 44 still in the opening 24, the door 11 still remains in a locked position.

In order to open the door 11, the proper key 20 is inserted into the slot 18 provided on the outside surface of the lock 10 or through the opening 21 on the surface of the lock 10. Now when the door knob 27 is rotated to open the door 11, the lock bolt support L will slide to the right, engage the rear wall 54 to slide the pin plate support P to the right. Now when the raised surface 19 arrives at the bevelled surface 36, the pins 60 will have been received by the openings 61 of the proper key 20. The pin plate support P will not become tilted and the pins 60 will remain in perfect alignment with the openings 62 in the punched back plate 25 as the knob 27 is continued to be rotated. The slide bolt 44 will now slide out of the opening 24 as the pins 60 slide into and are received by the openings 62 of the back plate 25 to unlock the door 11 as shown by FIGURE 7. Upon releasing the door knob 27 the coil springs 63 will return the lock bolt support and pin plate support P to the left to bring the lock 10 back to its locked position.

It is to be noted that there is a vast number of combinations available with the lock 10 constructed in accordance with my invention. The number of pins, the arrangement of pins and the configuration or cross sectional shapes of the pins 60 may be varied to produce millions of combinations wherein the key of one combination will not open the lock of another combination.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A combination lock comprising a housing, pin support means slidably mounted in said housing, lock bolt support means slidably mounted in said pin support means, means operating said lock bolt support means for unlocking said lock, a back plate having a plurality of openings removably mounted on said housing, a member having plurality of pins mounted on said pin support means in alignment with said openings in said back plate, means mounted on said housing normally causing the disalignment of said pins and said openings upon the movement of said pin support means a certain distance, and key means having opening substantially identical to those on said back plate mounted adjacent to said back plate whereby upon the movement of said pin support means said distance, said openings in said key means receive said pins and prevent the disalignment of said pins and said openings in said back plate and permit the unlocking of said lock.

2. The structure as recited by claim 1 wherein said means causing the misalignment of said pins and said openings in said back plate comprises a ridge portion mounted on said pin support means and said housing havin a slotted portion receiving said ridge portion.

3. The structure as recited by claim 2 wherein said lock bolt support means comprises a slide bolt extending through openings in said pin support means and said housing and spring means yieldingly urging said lock bolt to a locked position.

4. The structure as recited by claim 3 wherein said housing has slotted means for removably receiving said back plate and second slotted means adjacent said first slotted means for removably receiving said key means and further slotted means on said support means for removably receiving said pin supporting member.

References Cited UNITED STATES PATENTS 2,692,495 10/1954 Verdan 70-351 3,093,993 6/1963 Lord 70--352 MARVIN A. CHAMPION, Primary Examiner R. L. WOLFE, Assistant Examiner US. Cl. X.R. 70-385, 405 

